import org.apache.flink.ml.feature.ngram.NGram;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.table.api.Table;
import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;
import org.apache.flink.types.Row;
import org.apache.flink.util.CloseableIterator;
import java.util.Arrays;
/** Simple program that creates an NGram instance and uses it for feature engineering. */
public class NGramExample {
public static void main(String[] args) {
StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
StreamTableEnvironment tEnv = StreamTableEnvironment.create(env);
// Generates input data.
DataStream<Row> inputStream =
env.fromElements(
Row.of((Object) new String[0]),
Row.of((Object) new String[] {"a", "b", "c"}),
Row.of((Object) new String[] {"a", "b", "c", "d"}));
Table inputTable = tEnv.fromDataStream(inputStream).as("input");
// Creates an NGram object and initializes its parameters.
NGram nGram = new NGram().setN(2).setInputCol("input").setOutputCol("output");
// Uses the NGram object for feature transformations.
Table outputTable = nGram.transform(inputTable)[0];
// Extracts and displays the results.
for (CloseableIterator<Row> it = outputTable.execute().collect(); it.hasNext(); ) {
Row row = it.next();
String[] inputValue = (String[]) row.getField(nGram.getInputCol());
String[] outputValue = (String[]) row.getField(nGram.getOutputCol());
System.out.printf(
"Input Value: %s \tOutput Value: %s\n",
Arrays.toString(inputValue), Arrays.toString(outputValue));
}
}
}
# Simple program that creates an NGram instance and uses it for feature
# engineering.
from pyflink.common import Types
from pyflink.datastream import StreamExecutionEnvironment
from pyflink.ml.feature.ngram import NGram
from pyflink.table import StreamTableEnvironment
env = StreamExecutionEnvironment.get_execution_environment()
t_env = StreamTableEnvironment.create(env)
# Generates input data.
input_data_table = t_env.from_data_stream(
env.from_collection([
([],),
(['a', 'b', 'c'],),
(['a', 'b', 'c', 'd'],),
],
type_info=Types.ROW_NAMED(
["input", ],
[Types.OBJECT_ARRAY(Types.STRING())])))
# Creates an NGram object and initializes its parameters.
n_gram = NGram() \
.set_input_col('input') \
.set_n(2) \
.set_output_col('output')
# Uses the NGram object for feature transformations.
output = n_gram.transform(input_data_table)[0]
# Extracts and displays the results.
field_names = output.get_schema().get_field_names()
for result in t_env.to_data_stream(output).execute_and_collect():
input_value = result[field_names.index(n_gram.get_input_col())]
output_value = result[field_names.index(n_gram.get_output_col())]
print('Input Value: ' + ' '.join(input_value) + '\tOutput Value: ' + str(output_value))